Scope for a small circumsolar annular gravitational contribution to the Pioneer anomaly without affecting planetary orbits

Abstract

All proposed gravitational explanations of the Pioneer anomaly must crucially face the Equivalence Principle. Thus, if Pioneers 10 and 11 were influenced by anomalous gravitational effects in regions containing other Solar System bodies, then those bodies should likewise be influenced, irrespective of their shape, composition or mass. Although the lack of any observed influence upon planetary orbits severely constrains such explanations, here we aim to construct by computer modeling, hypothetical gravitating annuli having no gravitational impact on planetary orbits from Mercury to Neptune. One model has a central zone, free of radial gravitation in the annular plane, and an 'onset' beyond Saturn's orbit, where sunward annular gravitation increases to match the Pioneer anomaly data. Sharp nulls are included so that Uranus and Neptune escape this influence. Such models can be proportionately reduced in mass: a 1 % contribution to the anomaly requires an annulus of approximately 1 Earth mass. It is thus possible to comply with the JPL assessment of newly recovered data attributing 80 %, or more, of the anomaly to spacecraft heat, which appears to allow small contributions from other causes. Following the possibility of an increasing Kuiper belt density at great ranges, another model makes an outward small anomalous gravitation in the TNO region, tallying with an observed slight indication of such an effect, suggesting that New Horizons may slightly accelerate in this region.G.S.M. Moore ( ) · R.E.M. Moore

Astrophysics and Dark Matter Theory

“…Moore [44] had also considered the gravitational effect of a DM distribution Figure 7 were due to some additional gravitational force, oriented towards the Sun, it should have been noticed. This was proven in 2006 by Iorio and Guidice [45].…”

Gravitational anomalies in the solar system?

“…Despite the growing evidence towards a satisfactorily solution of the PA in terms of conventional non-gravitational effects peculiar to the two spacecraft, there are still researchers continuing to look for new gravitational physical mechanisms 162,[266][267][268][269][270][271][272] able to accommodate the PA. A positive feature of such attempts is that they are now explicitly dealing with the need of explaining why the PA does not show up in the orbital motions of the Solar system's bodies moving in the same regions where the anomaly manifested itself, a crucial issue that cannot be set aside.…”

The Pioneer anomaly in covariant theory of gravitation

“…One of them for the Pioneer 10 and 11 spacecraft is due to the recoil force associated with an anisotropic emission of thermal radiation off the vehicles [2][3]. The other explanations of Pioneer anomaly include new gravitational physical mechanisms [4][5][6][7][8][9][10].…”